Cable winch

ABSTRACT

A three-speed hydraulic winch includes a base, a drum support, a drum shaft mounted on the support, a cable drum rotatable on the drum shaft and means mounting the support on the base for reciprocation substantially parallel to the drum shaft. A cable guide pulley is rotatably mounted in a pulley block which is fixedly mounted on the base. An endless chain traverse means is coupled between the base and the support to reciprocate the support. Four hydraulic motors constitute the drive means, and are operable to rotate a gear having clutch teeth on one face engageable with clutch teeth on a flange of the drum, and a chain and sprocket drive interconnects the drum and the endless chain traverse means. The guide pulley is operatively associated with an angle sensing device controlling the pull of the winch and controlling the load on the drum to a constant predetermined maximum. When the clutch is disengaged and the drum is free to rotate, a disk brake is automatically engaged if there is no tension on the cable, to prevent cable over-ride and hang-up, and this brake is released responsive to cable tension. The clutch cannot be disengaged if the cable is under tension. An extension shaft may be provided for driving a capstan or any other device. The fixed positioning of the cable guide pulley on the base, combined with a traversing movement of the drum, provides for level winding without the cable sweeping across the support during winding on the drum or unwinding therefrom. The pull on the cable is always in line with the guide pulley and there is &#39;&#39;&#39;&#39;no side pull,&#39;&#39;&#39;&#39; thus maintaining the load at a minimum.

United States Patent [191 Pierce, Jr.

[451 Sept. 17, 1974 CABLE WINCH [76] Inventor: Wayne M. Pierce, Jr., 39 Christine Ter., Milford, Conn. 06460 22 Filed: Nov. 20, 1972 [21] Appl. No.: 308,165

[52] US. Cl 254/172, 254/173 R, 254/175.7 [51] Int. Cl 366d 1/48 [58] Field of Search 254/172, 173 R, 175.7, 254/175.5, 175, 174; 242/37, 158 R, 158.1, 158 B [56] References Cited UNITED STATES PATENTS 647,242 4/1900 Sprague 254/174 1,716,025 6/1929 Bleds0e.... 254/175 2,020,631 11/1935 Becker 254/175 X 2,462,972 3/1949 Johnson 254/175 3,095,183 6/1963 LeBus 254/175 3,466,013 9/1969 Smith 254/175.7 3,648,858 3/1972 Barron 254/172 X FOREIGN PATENTS OR APPLICATIONS 647,565 10/1962 Italy 242/158 B Primary Examiner-Richard A. Schacher Attorney, Agent, or FirmArthur A. March, Esq.

[57] ABSTRACT A three-speed hydraulic winch includes a base, a drum support, a drum shaft mounted on the support, a cable drum rotatable on the drum shaft and means mounting the support on the base for reciprocation substantially parallel to the drum shaft. A cable guide pulley is rotatably mounted in a pulley block which is fixedly mounted on the base. An endless chain traverse means is coupled between the base and the support to reciprocate the support. Four hydraulic motors constitute the drive means, and are operable to rotate a gear having clutch teeth on one face engageable with clutch teeth on a flange of the drum, and a chain and sprocket drive interconnects the drum and the endless chain traverse means. The guide pulley is operatively associated with an angle sensing device controlling the pull of the winch and controlling the load on the drum to a constant predetermined maximum. When the clutch is disengaged and the drum is free to rotate, a disk brake is automatically engaged if there is no tension on the cable, to prevent cable over-ride and hangup, and this brake is released responsive to cable tension. The clutch cannot be disengaged if the cable is under tension. An extension shaft may be provided for driving a capstan or any other device. The fixed positioning of the cable guide pulley on the base, combined with a traversing movement of the drum, provides for level winding without the cable sweeping across the support during winding on the drum or unwinding therefrom. The pull on the cable is always in line with the guide pulley and there is no side pull," thus maintaining the load at a minimum.

4 Claims, 9 Drawing Figures PAIENIED SE? 1 H974 SHEET 1 IF 4 FIGZ 1 CABLE WINCH FIELD OF THE INVENTION This invention relates to cable winches and, more particularly, to a novel and improved hydraulically driven cable winch which is free of disadvantageous features of prior art cable winches.

BACKGROUND OF THE INVENTION Cable winches are used for many purposes, including hoisting operations and the'drawing of underground cable through trenches, conduits and the like. Known cable winches, particularly those for drawing underground electrical cable, have some disadvantages and operational hang-ups. Among these may be mentioned the dragging of the cable across the winch platform by a traversing mechanism which is used to effect level winding and unwinding of cable during rotation of a cable drum. This action places an undesirable load on the level winding mechanism. Another disadvantage is the inability of known cable winches to maintain a constant loading on the cable.

When a cable is payed out under power, difficulty is experienced in preventing a wire rope or cable from piling up and from performing loose wrapping or unwrapping relative to the drum. Additionally, known winches are not easily removable and accessible as a unit for maintenance, inspection and repair.

SUMMARY OF THE INVENTION This invention relates to cable winches and, more particularly, to a novel and improved hydraulic driven winch particularly designed for the drawing of underground electric cable and free of the disadvantages of known prior art winches used for this purpose.

In accordance with the invention, a cable drum support is mounted on a base in a manner to provide for reciprocation laterally of the base and substantially parallel to the rotating axis of the drum. A cable guide pulley is rotatably mounted in a pulley block which is fixedly mounted on the base, and traverse means are coupled to the drum support and to the base to reciprocate the support relative to the base to effect level winding and unwinding of cable during rotation of the drum aand without the cable being dragged sideways or laterally across the base.

The driving means for the cable drum comprises, preferably, four hydraulic motors which may be connected in parallel, for high torque and low speed operation, in series, for low torque and high speed operation, or in parallel-series for an intermediate range. A valveoperated shifting system eliminates mechanical levers and gear boxes, with the gears being constantly in mesh to eliminate problems due to engaging, noise and gear wear, and permitting shifting without slipping.

This is substantial advantage over the prior art winches which rely upon mechanical shifting requiring a complete stop of the winch before shifting. Shifting with the winch of the invention can be remotely controlled in a simple manner whereas, in the prior art, remote control is either lacking or else requires expensive and cumbersome equipment, whether the winch is hydraulically or mechanically operated.

The cable guide pulley includes an angle sensing device which controls the pull of the winch, and maintains constant load on the winch at all times. Driving of the drum is effected by a gear driven by the drive means, and having clutch teeth on one face thereof engageable with clutch teeth on a face of the drum. When the clutch is disengaged and the drum is in a free wheeling condition, a disk brake is automatically engaged with a drum flange if there is no tension on the cable, thus preventing cable over-ride and hang-up. This brake is released when tension is applied to the cable.

A clutch interlock is provided in such a manner that the clutch cannot be disengaged if the cable is under tension, and also requires tension on the cable for paying out under power. This prevents pile up" of the cable and loose wrapping.

Optionally, an extension shaft, which continuously rotates with the winch may be provided whereby a capstan or any other device may be driven.

An object of the invention is to provide an improved cable winch particularly designed for the laying of underground electrical cable.

Another object of the invention is to provide such a winch which is free of the disadvantages of known prior art winches used for this purpose.

A further object of the invention is to provide such a cable winch in which the cable drum is reciprocated parallel to its axis to provide for level winding and unwinding of the cable during rotation of the drum and without a cable being drawn laterally across the drum support base and thus adding a heavy load to the level winding mechanism.

Another object of the invention is to provide such a cable winch which is removable as a unit from its support base for ready inspection, maintenance and repair.

A further object of the invention is to provide such I a cable winch in which cable pile up and loose wrapping are automatically prevented.

For an understanding of the principles of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a perspective view of a cable winch embodying the invention;

FIG. 2 is a back elevation view of the winch, corresponding to FIG. 1;

FIG. 3 is a side elevation view taken on the line 3-3 of FIG. 2;

FIG. 4 is a sectional view taken on the line 4-4 of FIG. 3;

FIG. 5 is a sectional view taken on tthe line 5-5 of FIG. 3;

FIG. 6 is a view taken on the line 6-6 of FIG. 1;

FIG. 7 is a view taken on the line 77 of FIG. 6;

FIG. 8 is a view taken on the line 88 of FIG. 1; and

FIG. 9 is a schematic wiring diagram of the interlock and control system of the winch.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, a winch embodying the invention is illustrated as comprising a base carrying a drum support having a drum shaft 25 rotatably mounting a cable drum 20. Base 10 is a generally rectangular structure including a bottom wall 1 1, side walls 12, a front strut 13 extending between side walls 12 and a traverse support rod 14 extending between side walls 12 rearwardly of strut 13. In a manner to be described, strut 13 and rod 14 support drum support 15 for lateral reciprocation or traverse relative to base 10. Cable C, wound on drum or unwound therefrom, passes through a cable guide 30 which is fixedly secured to strut 13, preferably at its midpoint. The hydraulic drive and control unit 50 for the winch is mounted at the rear end of base 10 and includes a high capacity hydraulic fluid reservoir 51 provided with a filter 52.

Drum support 15 comprises a front wall 16 interconnecting a pair of side walls 17, 17. In inwardly spaced and parallel relation to each sidewall 17, there is a respective inner side wall 17 and each pair of outer and inner side walls l7, 17', near its rear end, has secured thereto a respective trunnion 18 slidably engaging the tubular traverse shaft 14. Adjacent front wall 16, relatively narrow partitions 16 extend between each outer side wall 17 and the adjacent inner side wall 17 and, partition 16 in cooperation with front wall 16, rotatably mounts respective rollers 19 which ride on a track formed by front strut l3. Trunnions 18 and rollers 19 serve to support drum support 15 for reciprocation laterally of base 10 and parallel to the axis of rotation of drum 20. The traverse mechanism 40, for effecting such reciprocation or traverse, will be described in detail hereinafter.

A pair of tubular cross members 21 extend between each outer side wall 17 and its adjacent inner side wall 17, tubular cross members 21 being welded at opposite ends to the associated side walls. Each rear tubular member 21 is located at a substantially higher level than the associated front tubular member 21. Each tubular 21 has welded or otherwise secured thereto the outer end of an associated strut 22, and the inner ends of struts 22 are welded or otherwise secured to bearings 23 for drum shaft 25 rotatably mounting drum 20. Drum shaft 25 preferably is tubular.

Drum 20 comprises a pair of annular flanges 26, 26 whose inner peripheries are secured to respective bearings 27 engaged with shaft 25. A drum cylinder 28 extends between flanges 26 and 26 and is welded or otherwise secured thereto at its opposite ends, cylinder 28 having internal annular ribs 24, the outer ends of which are secured to bearings 27. The construction of drum 20 is best illustrated in FIG. 4.

Referring to FIGS. 1, 2, 3 and 4, a gear 35, having a diameter somewhat greater than the diameter of flange 26, is rotatably mounted on drum shaft 25 adjacent the outer surface of flange 26. Through the medium of a key 36 extending through relatively elongated diametrically opposite slots 37 in tubular shaft 25, and engaged in a channel-shaped recess in the inner surface of the hub 37 of gear 35, gear 35 is displaceable axially relative to flange 26. As best seen in FIG. 8, the outer surface of flange 26 has welded thereto radially inwardly directed clutch teeth 29 which are arranged to mesh with radially outwardly directed clutch teeth 38 on the inner lateral surface of gear 35. Thus, the flange 26 and the gear 35 cooperate to form a disengageable clutch, which is controlled electromagnetically as will be described hereinafter. Gear 35 meshes with the output or drive shaft 61 one motor of the four rotary hydraulic motors 60, mentioned above, and which are disposed in circumferentially spaced relation around the lower portion of gear 35 and are mounted in one set of side plates 17, 17' of drum support 15. While each of the motors can be mounted in any one of four positions, only one motor is shown, in FIG. 2 of the drawing. Gear 15 also constantly meshes with an idler pinion 62 which is in constant mesh with a pinion 56 secured on a shaft 55 rotatably mounted in bearings 57 secured to each outer side wall 17. At its right end, as viewed in FIG. 1, shaft 55 extends outwardly from one of t e motors with sa ansas gably. th isaa Prsr tecting sleeve 58 on the right side wall 12 of base 10, and its outer end is formed for coupling. It will be noted that capstan shaft 55 is continuously rotated whenever gear 35 is driven. Extension shaft 55 is slidably mounted for displacement with the winch, and can drive a capstan or any other device.

As best seen in FIGS. 1, 2, 3 and 4, flange 23 has secured thereto, in axially spaced relation, a chain sprocket 41 and a braking disk 46. Disk 46 is engageable by a disk brake 45, whose operation is described more fully hereinafter. An endless chain 42 is trained about sprocket 41 and about the input sprocket 43 of a gear box 44 mounted on the adjacent side wall 17 of drum support 15.

As best seen in FIGS. 2, 3 and 5, gear box 44 has a downwardly extending vertical output shaft 47 to the lower end of which are fixed two sprockets 48, 48 rotatably mounted in one part 53A of a two-part adjustable length support carried by a member 54 secured to the undersurface of drum support 15. A second pair of axially spaced sprockets 58, 58 are mounted on the outer end of the other part 538 of the adjustable length support, and endless chains 49 connect sprockets 48 to sprockets 58. A block 63 is secured to the endless chains 49 and has a pin extending downwardly therefrom and engaged in an elongated slot 66 in a block 64 secured to the bottom wall 11 of base 10. Slot 66 is elongated in a direction perpendicular to the axis of rotation of drum 20, and allows block 63 with pin 65 to move around the sprockets 48 and 58. With the described construction of the traverse mechanism 40, as drum 20 is rotated, chains 49 are driven and pin 65 is reciprocated laterally of drum support 15. However, as pin 65 is fixed against lateral movement with respect to bottom wall 11 of base 10, the travel of pin 65 causes drum support 15 to be reciprocated parallel to the axis of rotation of drum 20, thus effecting even winding of cable C on drum 20 and even unwinding of cable C from the drum.

It is this arrangement which permits the use of the fixed cable guide 30 which, as stated, is mounted in a fixed position on strut and of base 10. As best seen in FIGS. 6 an 7, cable guide 30 includes a support 31 fixed to strut l3 and rotatably mounting a cable sheave or pulley 32 under which cable C passes to and from drum 20. Pulley 32 is rotatably mounted on a shaft 33 which oscillatably supports a pendulous rocker 34 forming part of a cable tension sensing mechanism generally in dicated at 70. The tension sensing mechanism includes a relatively large diameter pulley 71, rotatably mounted on rocker 34, and a relatively small diameter pulley 72 rotatably mounted in an arm 73 rockable about the axis of rotation of pulley 71. Cable C, in passing from sheave 32 to drum 20, engages the pulleys or sheaves 71 and 72. Arm 73 has a portion engageable with the operator 74 of a normally closed switch 75 controlling application of disk brake 45 to brake disk 46. When cable C is under tension, arm 73 moves clockwise to open switch 75 through operator 74. However, when the cable becomes slack, arm 73 swings downwardly counterclockwise to release operator 74 so that switch 75 closes to apply disk brake 45 to brake disk 46.

Rocker 34, which comprises two parallel arms or plates, carries a cam portion 76 engageable with the operator 77 of a pilot valve 78 mounted on fixed support 31. The tension sensing mechanism sets the maximum load through displacement of cam portion 76. Such movement results from the fact that pulley 72 is not in a straight line between pulleys 32 and 71, so that it is displaced in accordance with the cable tension, resulting in angular displacement of rocker 34 and movement of cam portion 76 to operate pilot valve 78.

Pilot valve 78 controls the operation of the motors 60 in such a manner that, unless cable C is under tension, as sensed by the tension sensing pulley 72, cable drum cannot be power driven, or will not power out, when paying out cable C. This prevents kinking and flopping of the cable which might occur if drum 20 were power driven in a cable unwinding direction without there being tension on the cable.

All functions of the'winch, including operation of the clutch formed by gear 35 and flange 26' of drum 20, are controlled by remotely located electric switches. This remote control allows the operator to stand away from the winch and nearer the work area, for convenience and safety. The interlock control system is schematically illustrated in FIG. 9.

Referring to FIG. 9, the aforementioned clutch is indicated at 80, and is normally engaged but may be disengaged upon energization of its operating winding. Disk brake 45 also has an operating winding. Both brake 45 and clutch 80 are under the control of the tension sensing switch 75 which has an operator 75A which normally closes an upper pair of contacts. However, when tension is applied to cable C, operator 75A engages the lower pair of contacts. The supply of hydraulic fluid to the four motors 60 is either established or blocked by pilot valve 78. If cable C is under tension, switch 75 is opened to disconnect the clutch valve, and pilot valve 78 is open so that hydraulic fluid can be supplied to the motors in accordance with the setting of the controls. However, if cable C is slack, pilot valve 78 is closed, preventing supply of hydraulic fluid to the motors. All controls are electrically motivated.

The control current is supplied from a grounded source of potential, whose ungrounded terminal is indicated at 86. Terminal 86 is connected, through a safety switch 87, to the movable arm 85A of a main switch 85 which ccontrols the supply of power to the motor 60 as well as the direction of rotation thereof. In the illustrated position of arm 85A, the motors are deenergized. lf arm 85A is moved to engage contact 85B, the motors are operated in a direction to rotate drum 20 clockwise to draw in cable C and wind it on the drum and, if arm 85A is moved to engage contact 85C, drum 20, provided the cable C is under tension, is rotated counterclockwise to pay out cable C. For this purpose, contact 85B iis connected directly to one operating winding 81A of a reversing valve 81. The other contact 85C is connected to one of the lower contacts of switch and, if operator 75A is engaged with the two lower contacts, contact C of switch 85 is connected to the other operating winding 81B of reversing valve 81.

As previously mentioned, all four motors 60 may be connected in parallel to the source of hydraulic fluid under pressure for high torque and low speed operation of the winch. They also may be connected in series to the source for low torque high speed operation of the winch. For an intermediate speed range, the four motors are connected in series-parallel with each other. That is, the motors are connected in pairs in parallel to the source of hydraulic fluid under pressure, with each pair of motors including two motors connected in series with each other. The various connections are established by the valves 82, 83 and 84 which are electromagnetically operated and are under the control of a speed selector switch 90. For high speed operation, all three valves 82, 83 and 84 are closed. For the intermediate speed range, switch is operated to open valves 83 and 84 which establish the series-parallel connection of the motors. For a low speed operation, all three valves 82, 83 and 84 are opened, under the control of switch 90, so that all the motors 60 are connected in parallel to the source of hydraulic fluid under pressure.

A relay 78 has its energizing winding connected in parallel with the energizing winding of clutch 80 so that, when clutch 80 is disengaged by energization of its electromagnetic winding, horn relay 78 is energized. For free spooling of the drum, a free spool switch 91, which is a single pole double throw switch, is connected in series between safety switch 87 and the upper contacts of switch 75. With the described connections, when clutch 80 is disengaged and the winch is in a free spool condition, disk brake 45 is automatically engaged if there is no tension on cable C, thus preventing cable override and hang-up. Brake 45 is released when there is tension on cable C. The interlock is so designed that clutch 80 cannot be disengaged if the cable C is under tension, aand also to require tension in cable C for paying out under power. This prevents cable pile-up and loose wraps of the cable.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise withouut departing from such principles.

What is claimed is:

l. A cable winch comprising, in combination, a base; a drum support; a drum shaft mounted on said support; a cable drum rotatable on said drum shaft; means mounting said support on said base for reciprocation substantially parallel to said drum shaft; a cable guide pulley; a pulley block rotatably mounting said pulley and fixedly mounted on said base; drive means selectively operable to rotate said drum to feed cable to and from said drum over said guide pulley; traverse means coupled to said support and to said base and operable to reciprocate said support relative to said base parallel to said drum shaft to effect level winding and unwind ing of cable during rotation of said drum; driving mechanism interconnecting said drum and said traverse means; a capstan shaft rotatably mounted on said drum support in spaced parallel relation to said drum shaft and extending outwardly through a side wall of said base; the projecting end of said capstan shaft being designed for engagement by an operating tool to rotate said capstan shaft; a normally engaged clutch interposed between said drive means and said drum and including a clutch drive gear; and gearing continuously interconnecting said gear and said capstan shaft for rotation of said capstan shaft whenever said gear is rotated.

2. A cable winch, as claimed in claim 1, in which said drive means comprises hydraulic motor means driving one element of said clutch; and a pilot valve controlling supply of hydraulic fluid to said hydraulic motor means; said rocker including a cam cooperable with said pilot valve and operable, responsive to slack in the cable, to close said hydraulic valve to prevent supply of hydraulic fluid to said hydraulic motor means to arrest rotation of said drum.

3. A cable winch comprising, in combination, a base; a drum support; a drum shaft mounted on said support; a cable drum rotatable on said drum shaft; means mounting said support on said base for reciprocation substantially parallel to said drum shaft; a cable guide pulley; a pulley block rotatably mounting said pulley and fixedly mounted on said base; drive means selectively operable to rotate said drum to feed cable to and from said drum over said guide pulley; traverse means coupled to said support and to said base and operable to reciprocate said support relative to said base parallel to said drum shaft to effect level winding and unwinding of cable during rotation of said drum; driving mechanism interconnecting said drum and said traverse means; a normally engaged clutch interposed between said drive means and said drum; said drive means comprising hydraulic motor means driving one element of said clutch; and cable tension sensing means operatively associated with said cable guide pulley; said tension sensing means comprising a shaft rotatably supporting said guide pulley; a pendulous rocker oscillatably mounted on said pulley shaft; a pair of further pulleys rotatably mounted on said rocker and having the cable, trained over said guide pulley, passing over said further pulleys; a disk brake normally engaged with said drum to prevent rotation. thereof; and a normally closed switch effecting engagement of said disk brake with said drum; said rocker, responsive to tension in said 7 cable, engaging an operator of said normally closed switch to open said switch and, responsive to slack in the cable, disengaging said switch operator to effect closing of said normally closed switch.

4. A cable winch comprising, in combination, a drum support; a drum shaft mounted on said support; a cable drum rotatable on said drum shaft; hydraulic motor means in driving connection with said drum; cable tension sensing means operatively associated with the cable; a pilot valve included in said tension sensing means and controlling supply of hydraulic fluid to said hydraulic motor means and operable, responsive to slack in the cable, to prevent supply of hydraulic fluid to said hydraulic motor means and operable, responsive to slack in the cable, to prevent supply of hydraulic fluid to said hydraulic motor means to arrest rotation of said drum; said hydraulic motor means comprising:

four hydraulic motors operable to rotate said drum;

electromagnetically operated valve means selectively operable to connect said motors in parallel to a source of hydraulic fluid under pressure, for low speed high torque operation of said winch, to connect said motors in series to said source for high speed low torque operation of said winch, and to connect said motors in series-parallel to said source for intermediate speed operation of said winch; and

speed selector switch means connected in controlling relation with said electromagnetically operated valves. 

1. A cable winch comprising, in combination, a base; a drum support; a drum shaft mounted on said support; a cable drum rotatable on said drum shaft; means mounting said support on said base for reciprocation substantially parallel to said drum shaft; a cable guide pulley; a pulley block rotatably mounting said pulley and fixedly mounted on said base; drive means selectively operable to rotate said drum to feed cable to and from said drum over said guide pulley; traverse means coupled to said support and to said base and operable to reciprocate said support relative to said base parallel to said drum shaft to effect level winding and unwinding of cable during rotation of said drum; driving mechanism interconnecting said drum and said traverse means; a capstan shaft rotatably mounted on said drum support in spaced parallel relation to said drum shaft and extending outwardly through a side wall of said base; the projecting end of said capstan shaft being designed for engagement by an operating tool to rotate said capstan shaft; a normally engaged clutch interposed between said drive means and said drum and including a clutch drive gear; and gearing continuously interconnecting said gear and said capstan shaft for rotation of said capstan shaft whenever said gear is rotated.
 2. A cable winch, as claimed in claim 1, in which said drive means comprises hydraulic motor means driving one element of said clutch; and a pilot valve controlling supply of hydraulic fluid to said hydraulic motor means; said rocker including a cam cooperable with said pilot valve and operable, responsive to slack in the cable, to close said hydraulic valve to prevent supply of hydraulic fluid to said hydraulic motor means to arrest rotation of said drum.
 3. A cable winch comprising, in combination, a base; a drum support; a drum shaft mounted on said support; a cable drum rotatable on said drum shaft; means mounting said support on said base for reciprocation substantially parallel to said drum shaft; a cable guide pulley; a pulley block rotatably mounting said pulley and fixedly mounted on said base; drive means selectively operable to rotate said drum to feed cable to and from said drum over said guide pulley; traverse means coupleD to said support and to said base and operable to reciprocate said support relative to said base parallel to said drum shaft to effect level winding and unwinding of cable during rotation of said drum; driving mechanism interconnecting said drum and said traverse means; a normally engaged clutch interposed between said drive means and said drum; said drive means comprising hydraulic motor means driving one element of said clutch; and cable tension sensing means operatively associated with said cable guide pulley; said tension sensing means comprising a shaft rotatably supporting said guide pulley; a pendulous rocker oscillatably mounted on said pulley shaft; a pair of further pulleys rotatably mounted on said rocker and having the cable, trained over said guide pulley, passing over said further pulleys; a disk brake normally engaged with said drum to prevent rotation thereof; and a normally closed switch effecting engagement of said disk brake with said drum; said rocker, responsive to tension in said cable, engaging an operator of said normally closed switch to open said switch and, responsive to slack in the cable, disengaging said switch operator to effect closing of said normally closed switch.
 4. A cable winch comprising, in combination, a drum support; a drum shaft mounted on said support; a cable drum rotatable on said drum shaft; hydraulic motor means in driving connection with said drum; cable tension sensing means operatively associated with the cable; a pilot valve included in said tension sensing means and controlling supply of hydraulic fluid to said hydraulic motor means and operable, responsive to slack in the cable, to prevent supply of hydraulic fluid to said hydraulic motor means and operable, responsive to slack in the cable, to prevent supply of hydraulic fluid to said hydraulic motor means to arrest rotation of said drum; said hydraulic motor means comprising: four hydraulic motors operable to rotate said drum; electromagnetically operated valve means selectively operable to connect said motors in parallel to a source of hydraulic fluid under pressure, for low speed high torque operation of said winch, to connect said motors in series to said source for high speed low torque operation of said winch, and to connect said motors in series-parallel to said source for intermediate speed operation of said winch; and speed selector switch means connected in controlling relation with said electromagnetically operated valves. 